Mattingly was just 33 years old when she was found dead in her Texas home in April. Her sister, Christy Deweese, spoke to Fox News just days after a medical examiner determined that Mattingly committed suicide by a self-inflicted gunshot wound to the head.
"Just the fact that she did it is [surprising]," Deweese said. "We've known her addiction but we would have never thought she would have taken her own life."
An autopsy report obtained by Fox News confirmed "depressive writings" were found at the scene. Deweese said it's become clear to her that "you just don't know where anybody's mind is."
That's why Deweese and Mattingly's twin brother are now in the beginning stages of launching AJM S.A.F.E., a future nonprofit organization in Mattingly's memory to raise awareness about suicide.
"Our hope is to bring awareness to suicide, being there for anyone who may need a friend," Deweese said.
She said the organization hopes to provide support for "family and friends to help prevent it," in addition to making volunteers available for those who might be experiencing suicidal thoughts.
"It's always just important to reach out. We didn't expect that. The strongest person still has their demons," Deweese said in between tears.
One of the initiatives Mattingly's siblings hope to share when raising awareness is the "take five" method. She stressed the importance of taking five minutes out of every day to reach out to a friend, family member or co-worker to add a little brightness to their day.
"Just be aware," Deweese said of the siblings' initiative. "Suicide can take you by surprise. The AJM S.A.F.E. project asks people to take five minutes to reach out to a loved one or just say hello to try to make someone laugh. Just a couple minutes to reach out even if you don't think it's going to mean anything."
Deweese confirmed that although Mattingly's cause and manner of death have been released, a police investigation is still ongoing.
Mattingly's family has since been able to hold a small memorial service, but Deweese said they plan to hold a bigger service in the future once the coronavirus pandemic recedes.
If you or someone you know is having thoughts of suicide, please contact the National Suicide Prevention Lifeline at 1-800-273-TALK (8255).